The factor time in fetal heart rate monitoring and the detection of acidosis using the WAS score.

BACKGROUND: Using the naked eye evaluation of fetal heart rate (fhr) patterns remains difficult and is not complete. Computer-aided analysis of the fhr offers the opportunity to analyze fhr patterns completely and to detect all changes due to hypoxia and acidosis. It was the goal of this study to analyze the factor time in fetal monitoring and to evaluate the association between the fhr and the actual pH values in arterial umbilical blood. METHODS: During a period of 11 years the FHR signals (i. e., the R-R interval of the F-ECG) of 646 fetuses were recorded with a CTG and simultaneously by a computer. The computer files were analyzed thereafter, i. e., the results did not influence our clinical management. To enter the study, all fetuses must have been delivered by the vaginal route--in consequence without a significant loss of fhr signals. During forceps and/or vacuum deliveries recordings were continued. If necessary a new electrode was inserted. In this study recordings of fetuses with chorioamnionitis, tracings of malformed neonates and tracings shorter than 30 min were excluded. Thus 484 recordings were left. We used our own computer programs written in MATLAB (USA). 3 parameters were determined electronically: 1) the mean fetal frequency [fhf, (bpm)], 2) the number of turning points (N/min) in the fhr, which we called 'microfluctuation' (micro) and 3) the oscillation amplitude, oamp (bpm). Measurements of the acid-base variables from arterial (UA) and venous (UV) blood were performed using RADIOMETER equipment (ABL500) and trained personnel. However, only the actual pHUA values were used in this study. To detect the influence of hypoxia and acidosis, all 484 cases were separated into 7 groups according to the actual pH(UA) value: 55 fetuses lying in a small non-acidotic "pH-window" (pH(UA)=7.290-7.310, mean=7.300±0.008) were used as 'controls'. RESULTS: In humans fhf, micro and the oamp behave differently during the last 30 min of delivery and with different fetal pHUA values: micro is early (at 0 min) decreased with fetal acidemia and is steadily deceasing (68-40 N/min) during vaginal delivery; the oamp--mainly due to decelerations--is increased from 35 up to 70 bpm during the last 30 min. Hypoxia and acidosis increase the amplitude and duration of decelerations; finally fhf shows only an insignificant reaction to acidemia but is decreased (from 135 to 110 bpm) overall with the course of time. Therefore the 3 characteristics of the fhr might be ranged according to their decreasing sensitivity to acidemia as follows: 1) fetal microfluctuation, 2) oscillation amplitude and 3) mean frequency. The 3 components of the fhr were used to invent and apply a score named the WAS score. This score increases the association between the actual pHUA values and the activity of the fetal heart. The 3 variables of the fhr mentioned above were rated differently; the 3 factors necessary to achieve this were computed electronically using an optimization program. The result is the WAS score: WAS=mean [frq*f(f)(v(j)) * micro*f(m)(v(j))/oamp*f(a)(v(j))](j=1,30). Using the last 30 min of delivery the correlation coefficient r of this score with pH(UA) reaches 0.645, P<< 0.001. The regression is linear in our 484 cases. CONCLUSIONS: Microfluctuation is the most sensible variable of the fetal heart followed by the oscillation amplitude and mean frequency. The WAS score offers the best correlation with the actual pH values measured in arterial umbilical blood.

Fetal heart rate patterns during delivery complicated by hypoxia and acidosis - a computer-aided analysis.

BACKGROUND: Using the naked eye, evaluation of fetal heart-rate (FHR) patterns remains difficult and is not complete. Computer-aided analysis of the FHR offers the opportunity to analyse FHR patterns completely and to detect all changes possibly due to hypoxia and acidosis. It was the goal of this study to make these hypoxic changes of the FHR visible and to compare them directly with normal tracings. METHODS: During a period of 11 years the FHR signals (i. e., R-R intervals of the F-ECG) of 646 fetuses were recorded simultaneously also by a computer. The computer files were analysed thereafter, i. e., the obtained results had no immediate influence on the clinical management itself. To enter the study all fetuses must have been delivered by the vaginal route - in consequence without a significant loss of FHR signals. During forceps or vacuum deliveries recordings were continued. If necessary a new electrode was inserted. Recordings of fetuses with chorioamnionitis, tracings of malformed neonates and tracings shorter than 30 min were also excluded. No additional drugs were given to the mother during the time of recording. Thus 484 recordings were left. In this study only the last 30 min of each record were analysed off-line using our own computer programs written in MATLAB. Only 3 parameters were determined electronically: i) the mean fetal frequency (FRQ, bpm), ii) the number of turning points (N/min, see Fig. 1) in the FHR, which we called 'microfluctuation' (MIC) and iii) the oscillation amplitude of the FHR (OA, bpm, Fig. 1). Routine measurements of the acid-base variables from umbilical arterial (UA) and venous (UV) blood were performed using RADIOMETER equipments (ABL500) and trained personnel. To compare acidotic and non-acidotic FHR tracings, 2 pH groups were chosen: fetuses with a small non-acidotic "pH window" (pHUA=7.290-7.310) and 5 fetuses with severe acidosis, i. e., pHUA values <= 7.103. RESULTS: Using this narrow "pH-window" (7.290-7.310) shows that FRQ, MIC and OA belong together. The 3 variables are strongly associated with each other in a linear manner. All 3 correlation coefficients (r) are highly significant (P<0.001); in this context all 3 regressions seem to be linear. The mean pHUA in this special group amounts to 7.300±0.008 (N=50). In severe fetal acidosis (mean pHUA=7.051±0.060, N=5) MIC and OA are diminished significantly (P << 0.001) whereas the mean frequency is increased (ca.+6 bpm). Microfluctuation (MIC) seems to be the most sensible FHR parameter for the diagnosis of hypoxia and acidosis followed by OA and the fetal frequency niveau. CONCLUSIONS: In non-acidotic fetuses MIC, OA and FRQ belong together and their association can be described by the 3 basic principles presented above. Fetal reaction patterns during hypoxia and severe acidosis differ significantly when compared with tracings of non-acidotic fetuses. Computer-analysis reveals that MIC is the most sensitive FHR variable concerning hypoxia and acidosis followed by OA and the mean FRQ niveau. (Some of the acidotic recordings together with the WAS-score can be observed in full length at www.fhr-monitoring.org.).

Basic principles of the foetal heart rate during delivery without hypoxia and acidosis.

BACKGROUND: Using naked-eye evaluation of foetal heart rate (FHR) patterns remains difficult and is not complete. Computer-aided analysis of the FHR offers the opportunity to analyse the FHR completely and to detect all changes due to hypoxia and acidosis. In order to better understand these changes FHR patterns in non-acidotic foetuses should be studied by first separating FHR into (i) basal FHR (baseline) and (ii) all decelerations. METHODS: The FHR signals (i.e., R-R intervals) of 637 fetuses were recorded by a computer. To enter the study all foetuses must have been delivered by the vaginal route - in consequence without a significant loss of FHR signals. During forceps/vacuum delivery recordings were continued. If necessary a new electrode was inserted. Recordings of foetuses with chorioamnionitis and tracings of malformed neonates and tracings shorter than 30 min were excluded. No drugs were given to the mother during the time of recording. Thus 484 recordings were left. In this study only the last 30 min of each record were analysed using our own programmes written in MATLAB. 3 parameters were determined electronically: (i) the mean frequency (FRQ, bpm), (ii) the number of turning points (N/min), which we called 'microfluctuation' (MIC) and (iii) the oscillation amplitude (OA, bpm) (see Fig. 2). Computer analysis of the FHR offers the opportunity to separate baseline FHR from deceleration patterns using appropriate algorithms rearranging and sequencing all baseline segments (or all decelerations) to a new file. Therefore each of the 2 new files contains only one category of the FHR: baseline segments (with accelerations) only or decelerations only (Fig. 1). 1 min was always taken as the reference time interval. In order to exclude foetal hypoxia and acidosis during the last 30 min, a small pHUA -'window' was chosen (7.290 up to 7.310) using acid-base variables from umbilical arterial (UA) blood measured soon after delivery with RADIOMETER equipment (mainly ABL500) by trained personal. RESULTS: Overall 14,520 min of the 484 foetuses were analysed by measuring in UA blood (X ± SD):pH=7.262 ± 0.065, pCO2 = 53.7 ± 8.8 mmHg, BEEcf,ox=-3.3 ± 2.5 mmol/l and sO2 = 23.9 ± 12.4%. In the whole sample and in non-acidotic (pHUA: 7.29-7.31) foetuses (N=50) there exist 3 fundamental principles which combine the 3 FHR variables under investigation: (I) MIC is strongly associated (r=0.631, P << 0.0001) with mean FRQ (bpm): in ca. 40% of all foetal heart beats a turning of the vector occurs (Fig. 4). (II) MIC is associated also with OA (r = -0.480, P << 0.0001); this regression is non-linear: Smaller band-widths are associated with increased MIC [OA = 0.0027 × MIC2 - 0.56 × MIC + 71 (see Fig. 5)]. (III) In non-acidotic foetuses lowering of the mean frequency niveau is associated with increased OA (overall: r = -0.349, P<< 0.0001); Using baseline segments only: r = -0.283, Nmin=844, P<0.0001. This regression is linear again: OABL = -0.445 × FRQBL + 94.1. Overall a Delta frequency (ΔFRQ) of + 10 bpm leads to a ΔOA of -4.1 bpm. These 3 rules are valid in isolated baseline segments as well as during artificially isolated deceleration patterns. CONCLUSIONS: FHR is a unit and should be analysed by computer-aided technologies as a unit. MIC, OA and FRQ belong together and their interaction can be described in non-acidotic foetuses by the 3 basic principles given above. Standard FHR tracings remain untouched.

Sensitivity, specificity, receiver-operating characteristic (ROC) curves and likelihood ratios for electronic foetal heart rate monitoring using new evaluation techniques.

OBJECTIVE: Hypoxia and acidosis adversely influence many foetal organ functions. We wanted to know how foetal heart rate (FHR) patterns are mirrored by the fetal acid-base status and if they could serve for predicting the actual pH in umbilical artery (UA) blood. For this purpose we condensed the FHR phenomena into one figure which was to be used as a testing variable and to analyse the performance of the new testing procedure. METHODS: The direct FHR signals of 475 foetuses were stored in a computer and analysed offline (MATLAB). All foetuses were delivered by the vaginal route thus without a significant loss of signals. The last 30 min of each recording were used. Acid-base variables and blood gases were determined in cord blood (UA and UV) using RADIOMETER equipments. Three variables of the foetal heart rate (FHR) were computed for each minute: oscillation amplitude [oza (bpm)], microfluctuation [ozm (N/min)] and mean frequency [fhm (bpm)]. These variables were combined to a new index, which we call the WAS index: WAS(T)=FHM(T) x OZF(T)/OZA(T). Using optimisation programmes this index was tailored to actual pH, UA leading to the novel, adapted index: WAS(T)=[FHM(T) x GFHM] x [OZF(T) x GOZF] x [OZA(T) x GOZA]-1,where GFHM, GOZF and GOZA denote three mathematical functions comparable to boundaries in discontinuous scoring-procedures, e. g., the APGAR score. The mean of the WAS index for the last 30 min of delivery is called the WAS score and is used as a discriminator in the testing procedure. WAS score and measured pHUA-values were submitted to correlation and linear regression analysis. Sensitivity, specificity, likelihood ratios, and post-test probabilities were computed including their 95% confidence intervals (CI). A ROC analysis was performed by applying different thresholds for pHUA. RESULTS: pH and WAS score are normally distributed in this sample. The correlation coefficient (r) for pHUA and the WAS score amounts to 0.657, P<<10 (-4). Using ROC plots the area under the curve (AUC) is steadily increased with decreasing pHUA reaching 1.0 for pH 7.0 indicating excellent test accuracy. The AUC for pHUA=7.100 is already 0.963+/-0.066, 95% CI (0.942-0.978), P<0.001. The positive likelihood ratios (+LR) far exceed 10.0 when lowering the threshold for pHUA. Aiming at a sensitivity of 100% the discriminatory power of the test becomes clinically an optimum when using a discriminator of 1.816 and a threshold pH of 7.122: Sensitivity=100%, specificity=89.3%, FNR=0%, FPR(%)=10.7% and AUC=0.958+/-0.049, 95% CI (0.936-0.974), P<0.001. CONCLUSIONS: Computer-aided evaluation of FHR patterns leads to a novel index (WAS score) which predicts foetal acidaemia with a high level of accuracy. Therefore online WAS scoring is proposed as an ancillary test procedure for future evaluation of FHR patterns. The conventional EFM remains untouched.

[A new approach to quantitative electronic foetal heart-rate analysis]. / Ein neuer Weg zur quantitativen elektronischen CTG-Analyse.

BACKGROUND: Recently it was found that a significant correlation exists between the variables of the foetal acid-base balance (ABB) and the parameters of the foetal heart rate (FHR). This dependency can be used for diagnostic purposes. Until now FHR could be evaluated off- and online by computer using scoring procedures, i. e., discontinuous methods, which need considerable computational efforts since FHR must reliably be separated into baseline (BL), decelerations and accelerations. Therefore, the question must arise whether a continuous and less cumbersome evaluation of individual FHR-parameters might lead to even better results? METHODS: The last 30 min of 465 direct recordings of foetuses all delivered by the vaginal route were stored in a computer and analysed offline using our own MATLAB programmes. Five variables were computed for every single minute: The microfluctuation, the oscillation amplitude, the mean frequency, the sum of the absolute differences of time periods and the sum of the absolute differences of frequencies. In this paper the last two variables will be abbreviated 'total sums'. All minutes of a FHR tracing were treated equally i. e. there was no separation anymore between BL and decelerations (accelerations). In order to analyse the physiological intercorrelation of the five variables mentioned above a 'pH window' was chosen between 7.275 and 7.325 [7.275< or =pH, (umbilicalartery (UA)< or =7.325]. Thereafter, the influence of hypoxia and acidosis on the five variables was evaluated. According to the results obtained two of the five variables, the 'total sums', were not further analysed. Using the remaining variables 'frequency', 'oscillation amplitude' and 'microfluctuation' a new index, the WAS index, was created. This index offers the opportunity to evaluate the FHR continuously using 'coding lines' for each of the three parameters. The WAS index was designed according to the FHR characteristics of the awake (Wach), acidotic (Azidotisch) (pH, UA=ca. 7,000) and sleeping (Schlafend) foetus. Using the last 30 WAS indices covering the last 30 min of a single FHR tracing, a WAS score and the corresponding prognostic pH value was computed. These prognostic pH values were compared with the measured pH values of UA blood using again correlation analysis. RESULTS: Without any hypoxia and acidosis (pH, UA window) the five FHR variables are closely correlated with each other. Accepting minutes with decelerations only, the correlation between the 'total sums' and the remaining three parameters vanishes. Accepting hypoxia and acidosis (pH, UA > or =6.960) oscillation amplitude now offers the closest correlation with actual pH, UA (r=-0.440 p<<10 (-4)) followed by microfluctuation (r=0.224, p<0.001) and frequency (r=0.056, P: n. s.). This pattern is obviously due to the retention of all decelerations in the FHR tracings. The 'total sums' show less close correlations with pH, UA and BE(oxy) when compared with microfluctuation and oscillation amplitude (SumPER vs. pH, UA r=-0.125, p<0.001 and SumFRQ vs. pH, UA r=-0.154, p<0.001). All five variables under investigation show a better correlation with pH, UA when compared with BE(oxy) UA. The WAS score computed (mean) for the last 30 min of delivery leads to close correlations (p<<10(-4)) with all variables of the foetal ABB: pH, UA r=0.608; BE(oxy) r=0.535, pCO(2) r=-0.469 and sO(2) r=0.259. The median WAS score amounts to 0.176, the mean to 0.174+/-0.023; it is normally distributed in this sample. CONCLUSIONS: FHR characteristics in different foetal behavioural states offer the opportunity to design a new index, the WAS index, which shows close (p<<10(-4)) correlations with all variables of the foetal ABB. Thus, the pH value in cord blood can be predicted within clinically reasonable limits. The qualitative CTG analysis remains untouched.

Activation of a plant gene by T-DNA tagging: auxin-independent growth in vitro.

A transferred DNA (T-DNA) tagging vector with the potential to produce dominant mutations was used with cocultured Agrobacterium tumefaciens and protoplasts to tag genes involved in the action of the plant growth substance auxin. Transgenic calli were selected for their ability to grow in the absence of auxin in the culture media. From one experiment, 12 calli that displayed this phenotype were recovered, of which 11 were able to regenerate into plants. In one plant studied in detail, protoplast division in the absence of auxin genetically cosegregated with a single T-DNA insert. A messenger RNA encoded by a 6.4-kilobase sequence of plant genomic DNA rescued from the mutant is overexpressed relative to untransformed plants. The genomic DNA, as well as a cognate complementary DNA, once transfected into protoplasts promote growth and cell division in vitro in the absence of exogenously added auxin.

Growth of tobacco protoplasts stimulated by synthetic lipo-chitooligosaccharides.

fat Nodulation (Nod) factors are lipo-chitooligosaccharides (LCOs) secreted by rhizobia to trigger the early steps of nodule organogenesis in leguminous plants. A method to synthesize LCOs in vitro was developed. Synthetic LCOs alleviated the requirement for auxin and cytokinin to sustain growth of cultured tobacco protoplasts. LCOs containing C(18:1) trans-fatty acyl substituents were more effective than those containing cis-fatty acids in promoting cell division as well as in activating an auxin-responsive promoter and the expression of a gene implicated in auxin action. These data indicate that LCOs redirect plant growth also in nonlegumes by activating developmental pathways also targeted by phytohormones.

Modification of phytohormone response by a peptide encoded by ENOD40 of legumes and a nonlegume.

The gene ENOD40 is expressed during early stages of legume nodule development. A homolog was isolated from tobacco, which, as does ENOD40 from legumes, encodes an oligopeptide of about 10 amino acids. In tobacco protoplasts, these peptides change the response to auxin at concentrations as low as 10(-12) to 10(-16)M. The peptides encoded by ENOD40 appear to act as plant growth regulators.

Fluid regimens in the first week of life may increase risk of patent ductus arteriosus in extremely low birth weight infants.

BACKGROUND: High fluid volumes may increase neonatal morbidity. However, evidence supporting fluid restriction is inconclusive and restricting fluids may restrict caloric intake. OBJECTIVE: To determine if higher fluid intake was associated with increased risk of patent ductus arteriosus (PDA) or bronchopulmonary dysplasia (BPD) in extremely low birth weight (ELBW) infants. STUDY DESIGN: A total of 204 ELBW (170 ml kg(-1) day(-1)) in the first days of life is associated with increased risk of PDA.

Developmental and UV Light Regulation of the Snapdragon Chalcone Synthase Promoter.

Expression directed by the 1.1-kb snapdragon chalcone synthase (CHS) promoter linked to the [beta]-glucuronidase reporter gene has been studied in transgenic tobacco. The pattern of expression of the chimeric gene was compared with the expression of the endogenous CHS genes in tobacco and snapdragon. We demonstrate that expression of the CHS promoter is controlled in both an organ-specific and tissue-specific manner. The highest level of expression was observed in immature seeds. Deletions were used to define regions of the promoter required for expression in roots, stems, leaves, seeds, and flower petals of transgenic plants. We have defined the minimal sequences required for expression in different organs and mapped regions of the promoter that influence expression in either a positive or negative manner. A promoter fragment truncated to -39 activates transcription in roots of 4-week-old seedlings, whereas a fragment extending to -197 bp directs expression in petals and seeds. A positive regulatory element located between -661 and -566 and comprising a 47-bp direct repeat is active in all tissues investigated except petals. UV light-regulated expression in leaves of transgenic tobacco seedlings is dependent on the presence of sequences also required for leaf-specific expression. Within the intact promoter, sequences that individually confer different patterns of expression interact to produce the highly regulated expression pattern of CHS.

The alphabet soup of plant intracellular signalling: enter cyclic nucleotides.

Recent work reveals a role for cyclic nucleotides as secondary signalling molecules in a variety of signal transduction pathways in plants. Evidence is accumulating that cGMP is involved in signalling during photomorphogenesis and that cADP-ribose triggers the release of sequestered Ca2+ during the response of plant cells to abscisic acid. Though more tentative, cAMP has been proposed as playing an important role in ion channel activity and cell cycle progression. Taken together, a picture emerges of differing signalling pathways, possibility interacting with each other, acting on an array of developmental processes.

The impact of Ti-plasmid-derived gene vectors on the study of the mechanism of action of phytohormones.

The molecular basis of tumor formation on dicotyledonous plants by Agrobacterium relies on the transfer to the plant cell of a unique segment of bacterial DNA, the T-DNA. The T-DNA contains genes that are active in the plant cell and encode hormone biosynthetic enzymes, or proteins that deregulate the cell's response to phytohormones. Study of this process has yielded not only knowledge of how alterations in phytohormone homeostasis can affect plant cell growth, but also has provided the essential tools to study phytohormone signaling in transgenic plants. Furthermore, T-DNA insertion into the plant genome forms the basis of gene tagging, a versatile method for isolating genes involved in phytohormone signal transduction and action.

Patients with Glanzmann thrombasthenia lacking platelet glycoprotein alpha(IIb)beta(3) (GPIIb/IIIa) and alpha(v)beta(3) receptors are not protected from atherosclerosis.

BACKGROUND: Platelets have been suggested to play a role in the early development of atherosclerosis. As one test of this hypothesis, we assessed whether patients with Glanzmann thrombasthenia who lack platelet glycoprotein alpha(IIb)beta(3) (GPIIb/IIIa) complexes or both alpha(IIb)beta(3) and the more ubiquitous alpha(v)beta(3) cell membrane complexes are protected from development of atherosclerosis. METHODS AND RESULTS: Seven patients with Glanzmann thrombasthenia, 45 to 66 years of age, underwent bilateral carotid artery ultrasonography and screening for risk factors of atherosclerosis. Findings consistent with early atherosclerosis evaluated by measurement of intima-media thickness and presence of atherosclerotic plaques were observed in 6 of the 7 patients. Intima-media thickness values higher than the 75th and 90th percentiles of age- and sex-matched white control subjects of the Atherosclerosis Risk in Communities (ARIC) study were observed in 30 and 8 of 56 carotid artery measurements, respectively. Five of the 6 patients with signs consistent with early atherosclerosis lacked both alpha(IIb)beta(3) and alpha(v)beta(3) complexes and 1 only lacked alpha(IIb)beta(3). CONCLUSIONS: Glanzmann thrombasthenia does not protect affected individuals from development of atherosclerosis.

Metabolic and hemodynamic effects of metformin and glibenclamide in normotensive NIDDM patients.

OBJECTIVE: To compare the metabolic and hemodynamic effects of metformin and glibenclamide in normotensive NIDDM patients. RESEARCH DESIGN AND METHODS: After a 2-wk run-in period on dietary treatment alone, 12 Chinese normotensive patients with uncomplicated NIDDM were randomized to receive either metformin, or glibenclamide for 4 wk before being crossed-over to the alternative treatment for an additional 4 wk. Metabolic and hemodynamic index, including cardiac output estimation by impedance cardiography, were measured at baseline and at the end of each treatment period. RESULTS: Body mass index was reduced more with metformin than with glibenclamide, although glycemic control was similar with both drugs. Plasma total cholesterol concentration fell more with metformin (mean difference -0.65 mM, 95% confidence interval -0.96 to -0.32) than glibenclamide (mean difference -0.20 mM, 95% confidence interval -0.54-0.12) (P < 0.05). Compared with baseline values, erect diastolic blood pressure was reduced more by metformin (12.9% [95% confidence interval -21.5 to -4.4%]) than glibenclamide (-6.8% [95% confidence interval -14.9 to 1.2%]) (P < 0.001). The relative changes in the systemic vascular resistance index also differed between the two treatments (glibenclamide, 6.2 [-4.3 to 16.6%]; metformin, -1.2 [95% confidence interval -8.8-6.4%]) (P < 0.05)]. CONCLUSIONS: In normotensive NIDDM patients, treatment with metformin was associated with greater reductions in body weight, plasma total cholesterol concentration, and erect diastolic blood pressure, whereas the systemic vascular resistance index increased after treatment with glibenclamide. These findings merit long-term investigation.

Cardiovascular effects of a new inotropic drug in dog and normal man.

Cardiovascular effects of 1-butyl-3(1-(6,7-dimethoxyquinazolin-4-yl) piperidin 4 yl urea) (BDPU) were studied in 16 anesthetized dogs and in 7 healthy male volunteers. In animal experiments intravenous doses of 100, 250, and 500 mug/kg/min produced dose-related, significant increases in cardiac output and peak left ventricular dp/dt. No changes in heart rate and blood pressure occurred at 100 mug/kg/min, whereas higher doses caused falls in both systolic and diastolic blood pressures, accompanied by significant rises in heart rate. Inotropic effects could also be demonstrated in man. Changes of the systolic time intervals were dose-related and began at 64 mug/kg/min. At 250 mug/kg/min, the highest dose administered, the pre-ejection period decreased by 14.8 +/- 4.42 msec and its ratio with left ventricular ejection time by 0.049 +/- 0.017 against their respective control values (p less than 0.01). In contrast to animal experiments, no hypotension or tachycardia was observed in any subject. Pharmacokinetic studies showed a plasma elimination half-life of 76 +/- 3 min (mean +/- SE). There were no subjective side effects and standard laboratory tests were not altered, but there was a slight but significant rise in the urinary enzymes, lactic dehydrogenase (LDH) and glutamic oxaloacetic transaminase (GOT), which persisted up to 7 days.

Genes involved in the control of growth and differentiation in plants.

The mechanisms underlying totipotency, the unique ability of isolated plant cells to regenerate into plants, offer developmental biology a unique challenge. While it has been recognised for some time that phytohormones, such as auxin and cytokinin, play a role in this process by inducing a variety of growth patterns in both isolated cells, unorganised callus and intact plants, the molecular basis of their action remains unknown. The molecular and biochemical analysis of the novel interaction between tumour-inducing soil bacteria and the wounded plant has provided a valuable insight into how plants respond to phytohormones. During tumour formation, the bacteria transfer to the genome of the host plant a variety of genes which either short circuit the normal pathways of accumulation of phytohormones or modify how the plant cell responds to them. In parallel to these studies, we have been investigating plant genes involved directly or indirectly in the mechanism of phytohormone action. Auxin-binding proteins (putative receptors) have been localised in various cellular locations and the genes encoding them are currently undergoing analysis. Recently, a novel form of T-DNA has been devised by which mutant plant cell lines can be generated which grow in culture in the absence of exogenously applied auxin. The tagged genes, which are in effect plant cellular proto-oncogenes, are likely to shed more light on how auxin serves to regulate growth and development.

Geminivirus-based shuttle vectors capable of replication in Escherichia coli and monocotyledonous plant cells.

Shuttle vectors have been constructed that are able to replicate in either Escherichia coli or plant cells. They contain the ColE1 origin of replication and parts of the wheat dwarf virus genome, a geminivirus infecting a variety of species of monocotyledonous plants. Such plasmids are able to replicate in E. coli and wheat cells. The plasmids can be rescued in E. coli and show no changes during their passage through plant cells. Such an E. coli/plant cell shuttle vector system could be used for the amplification of foreign genes in plant cells, for studies on DNA rearrangement or the isolation of plant transposons.

Vascular insufficiency quantitatively aggravates diabetic neuropathy.

The effect of lower-limb ischemia on the severity of neuropathy was examined in 48 diabetic patients with peripheral vascular disease. The severity of the vascular disease, as determined by medical history, physical findings, and laboratory data, was scored for each leg. Neuropathy was rated clinically and based on the results of nerve conduction studies of the common peroneal, posterior tibial, and sural nerves. A significant correlation was found between the vascular scores and neurologic variables of the two legs, most strikingly so in electrophysiologic data, with coefficients of .6 to .7. Nondiabetic control patients showed no evidence of neuropathy, regardless of the severity of ischemia, whereas diabetic controls without limb ischemia showed symmetrical neuropathy. These findings support the hypoxic theory in the pathogenesis of diabetic neuropathy.

Noninvasive evaluation of microcirculatory hemodynamic changes during hemorrhage followed by saline or blood transfusion.

The purpose of the study was to examine the ability of a system combining laser Doppler flowmetry (LDF), photoplethysmograph (PPG), and transcutaneous oxygen tension (tc-PO2) to follow changes in the microcirculation during hemorrhage and following blood or saline return, and to test the hypothesis that such changes precede and might predict changes in the systemic blood pressure. Measurements were performed on the skin of anesthetized rabbits (n = 10) during mild (0-8%), moderate (9-24%), and severe (25-30% of blood volume) hemorrhage, and following complete volume restitution by blood or saline. We found the following: 1) hemorrhage caused typical changes in the LDF, PPG, and tc-PO2 signals that could be formulated by mathematical models, 2) these signals identified blood as being more efficient than saline for volume restitution following hemorrhage, and 3) microcirculatory changes precede and might predict systemic hemodynamic events.

Qualitative evaluation of antegrade percutaneous transluminal angioplasty by pressure waveform parameters.

When percutaneous transluminal angioplasty (PTA) is performed in an antegrade ("downstream") direction, intraluminal gradient measurements across the stenotic segment are not possible. Pressures recorded proximal to the lesion were evaluated for possible hemodynamic clues of changes in flow in ten consecutive patients before and after PTA. In all patients in whom the procedure was successful, the systolic pressure decreased by an average of 35 mm Hg. This decrease was not evident in the failed procedures. It is concluded that proximally recorded pressure changes can be used as an objective criterion to assess the success of PTA performed in arteries.